Dynamometer system for testing performance of drilling tools

A test system for testing a downhole drilling tool during a test, comprising:

• a test fluid source containing a test fluid;
• a test stand to hold the downhole drilling tool having a nonrotatable part including a mud motor and a rotatable part including a bit box, a drive shaft configured to be rotated by the mud motor rotates the bit box, wherein the mud motor is in fluid communication with the test fluid source to operate the mud motor to translate a rotational motion to the drive shaft;
• a reactive assembly including a rotatable housing and a nonrotatable housing, a torque transfer shaft, extending through the rotatable housing and the nonrotatable housing, having a first end in the rotatable housing and a second end in the nonrotatable housing, wherein the first end of the torque transfer shaft rotatably connected to the drive shaft at the bit box so that as the torque shaft is rotated by the rotational motion received from the mud motor both the bit box and the rotatable housing rotate during the test;
• a torque load test tool of the test system to apply torque loads to the downhole drilling tool during the test, the torque test tool includes a pump having an actuator rotationally coupled to the second end of the torque transfer shaft to receive the rotational motion from the mud motor to run the pump, the pump receives the test fluid from the test fluid source through a pump inlet valve and discharge it as a discharge flow from a pump discharge valve;
• a control valve being configured to selectively apply a braking force to the pump by restricting the discharge flow so as to apply torque loads the downhole drilling tool;
• a side load tool of the test system to apply side loads to the drilling tool during the test;
• and
• a thrust load tool of the system to apply thrust loads to the drilling tool during the test.